Many functions of modern devices in automotive, consumer and industrial applications, such as converting electrical energy and driving an electric motor or an electric machine, rely on power semiconductor switches. For example, Insulated Gate Bipolar Transistors (IGBTs), Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) and diodes, to name a few, have been used for various applications including, but not limited to switches in power supplies and power converters.
A power semiconductor device usually comprises a semiconductor body configured to conduct a load current along a load current path between two load terminals of the device. Further, the load current path may be controlled by means of an insulated electrode, sometimes referred to as gate electrode. For example, upon receiving a corresponding control signal from, e.g., a driver unit, the control electrode may set the power semiconductor device in one of a conducting state and a blocking state. In some cases, the gate electrode may be included within a trench of the power semiconductor switch, wherein the trench may exhibit, e.g., a stripe configuration or a needle configuration.
It is usually desirable to keep losses, e.g., switching losses, on-state losses during a conducting state and off-state losses during a blocking state of the power semiconductor device low.
Further, a power semiconductor device may be designed to continuously operate under nominal conditions, according to which, e.g., a load current does normally not exceed a nominal value for more than a predetermined time period, and a voltage applied between the two load terminals does normally not exceed a nominal value for more than a predetermined time period.
It is usually tried to avoid that the power semiconductor device becomes subjected to a voltage significantly higher than the nominal blocking voltage it has been designed for, regarding transient state (e.g., switching) situations as well as continuous blocking state situations. To this end, some overvoltage protection concepts have been developed in the past, one of which is generally known as “clamping”. For example, a so-called Transient Voltage Suppressor Diode (TVS Diode) can be used in order to reduce transient overvoltages that may occur during a transistor switching operation.